Change amplifying means



Nov. 15, 1938. J. w. DAWSON CHANGE AMPLIFYING MEANS Original Filed 00$. 25, 1955 INVENTOR .f0/2/7W awsan WITNESSES:

' Patented Nov. 15, 1938 UNITED STATES PATENT OFFICE 2.1 1.043 cannon mmrrmo MEANS John W. Dawson, East McKeesport, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania 'lclaims.

My invention relates to means for amplifying voltage changes in electric circuit systems and it has particular application to means suitable for use with voltage adjusting or regulating mechanlsms.

This application is a division of my copending application Serial No. 46,351 for Change amplifying means, filed October 23, 1935, and assigned to the same assignee of this application.

An object of my invention is the provision of highly sensitive means for amplifying a variable characteristic of an electric circuit. I

Another object of my invention is the provision of mechanism having the desired high sensitivity characteristic which lends itself to ready advjustment in the degree of amplification desired.

A further object of my invention is the accomplishment of the above stated results by the use of relatively inexpensive equipment employing non-movable parts.

Other objects and advantages of my invention will be apparent from the following description of certain embodiments thereof, reference being had to the accompanying drawing, in which:

Figure 1 is a diagrammatic illustration of apparatus and circuits embodying a preferred form of the invention,

Fig. 2 is a diagram oi a curve illustrating the high sensitivity characteristics of the equipment illustrated in Fig. 1, and 4 1 Fig. 3 is a diagrammatic view of apparatus and circuits illustrating another preferred embodiment of the invention.

Referring to the drawing and particularly to Fig. 1 thereof, supply conductors l and 2 are provided that are adapted to be connected to an alternating current source of supplied voltage E1 and between which are connected the windings 3 and 4 of a reactor 5 and an impedance 6 in series circuit relation. The reactor 5 may, as

illustrated, be of the type employing three 'core legs, the windings 3 and 4 surrounding the two outer legs and a saturating winding 1 being provided on the middle leg that is connected by conductors 8 and 9 to a resistor I2, a slidable contact I! being provided to vary the point of connection between the conductor 9 and the resistor l2.

A full wave rectifier I4 is provided, the direct current terminals l5 and it of which are connected to the terminals of the resistor i2 and the alternating current terminals I1 and i8 of which are connected to the terminals of the impedance device 6 to be energized with alternating current in accordance with the voltage impressed across the device I. Conductors l9 and 2| comprising an output circuit are also connected to the direct current terminals I5 and I6, respectively, of the rectifier l4. 1

In operation, the input voltage E1 .that is impressed across conductors I and 2 divides itself between the series connected elements 3, 4 and G in a manner determined by their relative impedances. When the impressed voltage E1 is of an intermediate value, the corresponding core saturating current supplied to the reactor winding I and which is determined by the voltage E2 across the impeder 6 causes the impedance of the reactor winding 3 and 4 toalso assume an intermediate value.

As the magnitude of the impressed voltage E1 is increased the potential E2 is also increased, thus increasing the current through the winding I of the reactor 5 and correspondingly increasing the degree of saturation of the reactor core to lower the impedance of the reactor windings 3 and 4, thus reducing the voltage drop across them and causing a greater proportion of the total impressed voltage E1 to appear across the impedance device 6. Consequently, the voltage E: applied to the rectifier l4 and the voltage E3 supplied tothe output circuit are increased by an amount that is more than proportional to the increase in the impressed or input voltage E1.

, Similarly, as the input voltage E1 decreases the voltage E2 also decreases thus decreasing the unidirectional current supplied to the winding 1, thereby decreasing the saturation of the reactor core and the impedance of the windings 3 and 4. The increase in the impedance of the windings 3 and 4 results in a lesser portion of the total voltage E1 being impressed across the impedance device 6, so that the potential E2 and the potential E3 are decreased an amount that is more than proportional to the decrease in the applied voltage E1.

The degree in the amplification of the output circuit voltage with respect to the input voltage that is readily attainable is shown by the curve 22 in Fig. 2, that is plotted from test data obtained from an embodiment of the invention corresponding to that illustrated in Fig. 1. It will be observed that as the total impressed voltage E1 is increased from to say volts, the output voltage E3 may be increased from 100 to volts, and that a decrease in the impressed voltage E1 from 100 to 90 volts results in a decrease in the output voltage E: from 100 to 60 volts. The curve 22 in Fig. 2 is illustrative only and will vary somewhat in different designed embodiments of the invention but is sufficient to M illustrate that a relatively small change in the input voltage E; from a normal or intermediate value represented as 100 causes a relatively large change in the same direction of the output voltage E3.

The embodiment of the invention illustrated in Fig. 3 is, in general, similar to that illustrated in Fig. 1 but provides an impedance device 23 in addition to the impedance device 6 and the windings 3 and 4 in series circuit relation between the conductors i and 2 across which the input. voltage is supplied. Current is supplied to the rectifier H at the voltage E: for saturating the winding 1 of the reactor 5 and current is supplied to the output circuit in accordance with the voltage appearing across the inductor 23. Also in the embodiment illustrated in Fig. 3 the output conductors 24 and 25 are connected directly across the impedance device 23 without employing a rectifier so that the output voltage E4 is an alternating voltage instead of a unidirectional voltage. It will be apparent that a rectifier similar to H might be connected between the conductors 24 and 25 to supply a unidirectional current to an output circuit, if desired.

In both embodiments of the invention the degree of amplification may be readily changed by altering the position of the contactor ,l3 along the resistor l2, thus changing the reactance of the windings 3 and l for a given change in the voltage impressed across the impedance device 6. Movement of the contactor l3 upwardly along the resistor ii to increase the proportional voltage thereacross upon the windings I increases the amplification factor and a movement of the contactor l3 downwardly correspondingly lowers the amplification factor. By amplification factor is meant the percentage change in output circuit voltage from the value 100, as indicated in Fig. ,2 upon the same change in impressed or input voltage E1 from the value 100.

It will be apparent that the voltage change amplifying means illustrated in Figs. 1 and 3 are useful in many applications where it is desired to magnify variations in an impressed alternating current potential.

The illustrated regenerative reactor circuits and apparatus are, therefore, adapted for a wide variety of uses in control and regulating applications.

Although I have illustrated and described certain specific embodiments of my invention, I am aware that many modifications thereof within the spirit of my invention will appear to those skilled in the art, and I do not wish to be limited otherwise than by the scope of the appended claims.

I claim as my invention:

1. In combination, an output circuit, an input circuit supplied with alternating current, a regulating reactor and an impedance device connected in series in said input circuit, and means responsive to a voltage change across said impedance device initiated by a change in the voltage impressed on said input circuit for varying the reactance of said regulating reactor in a direction to cause a further change in voltage across said impedance device in same direction to thereby amplify the voltage variations of said output circuit with respect to voltage variations of said input circuit.

2. In combination, an output circuit, an input circuit supplied with alternating current, a regulating reactor and an impedance device connected in said input circuit, said reactor being of the multiple leg core type provided with a saturating winding on one leg, means responsive to voltage changes in the input circuit for producing a change in the degree of saturation of the reactor in the same direction as voltage changes in the input circuit for amplifying the voltage variations of said output circuit with respect to voltage variations of said input circuit comprising a rectifier having its alternating current terminals connected to receive current at a voltage that varies in accordance with the voltage across said impedance device, a resistor connected across the direct-current terminals of said rectifier, and means including a sliding contact for supplying current to the saturating winding of said reactor at a selected proportion of the voltage across said resistor.

3. In combination, an output circuit, an input circuit supplied with alternating current, a regulating reactor and an impedance device connected in said input circuit, said reactor being of the multiple leg core type provided with a saturating winding on one leg, means for amplifying the voltage variations of said output circuit in response to voltage variations of said input circuit comprising means for causing the saturating flux to vary in the same direction as the voltage across said impedance device, and means for supplying a unidirectional current to said output circuit including a rectifier supplied with alternating current at a voltage that varies in accordance with the voltage across said impedance device.

4. In combination, an output circuit, an input circuit supplied with alternating current, a regulating reactor and two impedance devices connected in said input circuit in series circuit relation, said reactor having a saturating winding, means responsive to the voltage across one of said impedance devices for causing the saturating flux of said regulating reactor to vary in the same direction for amplifying the voltage variations of said output circuit with respect to voltage variations in said input circuit comprising means for supplying a current to the output circuit at a voltage that varies in accordance with the voltage across the other of said impedance devices.

5. In combination, an output circuit, an input circuit supplied with alternating current, a regulating reactor and two impedance devices connected in series circuit relation in said input circuit, said reactor being of the multiple leg core type provided with a saturating winding on one leg, means for amplifying the voltage variations of said output circuit with respect to voltage variations of said input circuit comprising a rectifierfor supplying a unidirectional current to the saturating winding of the reactor for causing the saturating flux to vary in accordance with the voltage across one of said impedance devices, and means for supplying a current to said output circuit at a voltage that varies in accordance with the voltage across said other impedance device.

6. Means for amplifying magnitude variations in an alternating-current voltage comprising a reactor having a core saturating winding, two impeders, a circuit for connecting said impeders in series with the reactor for energization by a measure of said voltage, and means for supplying to the saturating winding of the reactor a current determined by the voltage appearing across one of the impeders for producing a change in the degree of saturation of the reactor in the same direction as voltage changes across said impeder whereby the voltage appearing across the other impeder is caused to follow in intensified degree changes in the magnitude of the alternating current voltage first named.

'7. Means for amplifying magnitude variations in an alternating voltage comprising a circuit including two impedance devices and a regulating reactor in series circuit relation to which said voltage is applied, said reactor comprising a multiple leg core having a saturating winding on one leg thereof, means including a rectifier for supplying unidirectional current to the saturating winding determined by the voltage appearing across one of said impedance devices for producing a change in the degree of saturation of the reactor in the same direction as voltage changes across said impedance device, and means for effecting an output voltage determined by the voltage appearing across the other of said two impedance devices.

JOHN W. DAWSON. 

